1. Field of the Invention
This invention relates to a device for underpressuring collection and dosage liquid samples, in particular for collection blood samples from a patient""s vein for analytic tests or dosage remedy liquids into a blood vascular system or any body cavity.
2. Description of the Related Art
The European patent No. 0191945 discloses a blood sampling device comprising a cylindrical sample tube and slidable therein a plunger and also comprising an end cap on which there is eccentrically disposed an axially directed cone. The device comprises an adapter fitted on the cone and having two cannulae secured thereon, the outer cannula being free for introduction into a vein while the inner cannula is closed by a tyre valve. The device comprises also a non-return valve which is disposed in the end cap and which consists of an elastically deformable diaphragm having a central valve aperture and a cylindrical support ring for the diaphragm, said ring being inserted into the end cap, the diaphragm and the support ring being constructed as a one-piece diaphragm ring and the diaphragm being disposed in the support ring so as to be inwardly offset and being externally formed as a spherical segment such as to project somewhat beyond the edge of its support ring and a circular valve seat integrally formed concentrically on the inside of the end cap.
Further, the publication of the international application No. WO 95/16395 discloses a holding fixture for a blood sample collection tube of a blood-taking device which has a collecting container, with needle carrier, for a front end of the blood sample collection tube, which is closed off by a closure device. Mounted in the needle carrier is a syringe directed toward the opened end of the collecting container and projecting in its direction. A connecting passage formed between the needle carrier and a front wall of the collecting container links a flow channel with a collecting needle of a needle arrangement that is eccentric to a central longitudinal axis of the collecting chamber. As required, an openable valve arrangement is situated between the connecting passage and a collecting chamber. This valve arrangement is formed by a tube valve or flap valve disposed between the syringe and the collecting container and/or the connecting passage. The syringe is preferably set concentric to the collecting container. The flow channel feeds into the connecting passage between the syringe and an outer wall of the collecting container.
According to the present invention, a device for underpressuring collection and dosage liquid samples, in particular for analytic tests, comprises a holder with a blood sample collection tube-syringe on the one side and a needle arrangement on the other side, the holder comprises a set of two valves, the first valve on the tube-syringe""s side being a tyre valve and the second valve on the side of the needle being a membrane valve which has a membrane placed on an under-support with side-inlets.
The device according to the invention further comprises a guide bar of the holder which is open on the one side and on the other side has a conic head for the needle and a seating within the guide bar, the membrane valve being placed on a side of a frontal surface of the seating and on the other side there is placed the tyre valve comprising a inner needle covered by a tyre. The membrane and the under-support are placed in a recess on the frontal surface of the seating.
The device according to the invention has also an under-membrane chamber in the seating under the membrane. The under-support has a form of a sleeve with side-inlets or is formed by a number of separate supports which are distributed in the same distance from the axis of the membrane. The thickness of the membrane is considerably smaller in its periphery than in its central part, in particular, the thickness of the membrane is smaller outside the under-support.
In the present invention the axis of the inner needle is in principle in line with the axis of the membrane and the conic head has on the seating""s side a top-support of the membrane whose position is in line with the position of the under-support.
The holder, in the device according to the invention, has a shield which is placed on the guide bar of the holder and has an opening for the conic head in its top part. The shield is joined with the guide bar by upper latches and lower latches and there is a security container for the needle. The shield has in its upper part an observation window for the observation of collected liquid. Moreover, the shield and the guide bar have in their lower part an opening for the observation of a liquid material in the tube-syringe inserted into the holder, the guide bar has in its lower part a stabilising flange. In a rubber plug of the tube-syringe a cleaning chamber is placed.
In the device according to the invention, between the conic head and the needle, there is placed an opening needle head comprising a conic sleeve having a head part which is formed as the conic head of the holder and a lower part which is placed on the conic head of the holder, wherein inside of the conic sleeve in its lower part is placed an opening needle. The axis of the opening needle passes through the membrane and is in principle in line with the axis of the inner needle.
An advantage of the solution according to the present invention is a fact that after inspection of the correctly performed injection into blood vascular system or any body cavity in the observation window, the liquid material flows into the blood sample collection tube-syringe in an unconstrained manner and it cannot flow back. Moreover, the shield of the holder is a safety container for a used needle. The device according to the invention may be used also for dosage remedy liquids with an added opening needle head.